Railway traffic controlling apparatus



May 2, 1939.

R, A. M CANN RAILIWAY TRAFFIC CONTROLLING KPPARAQUS Filed July 181 1956 INVENTOR Ronald Q CLZDH.

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Q a ma E Patented May 2, 1939 UNITED STATES PATENT OFFICE RAILWAY TRAFFIC CONTROLLING APPARATUS Application July 18, 1936, Serial No. 91,256

4 Claims.

My invention relates to railway traffic controlling apparatus, and more particularly to apparatus for use in connection with centralized V traffic controlling systems for railroads. In systems of this character, it is customary to govern the operation of railway signals and switches situated at remote points from a central control point, usually the dispatchers ofiice, and it frequently occurs that junctions, yards, or the like, at'which local switching is to be done and at which local operators are continuously on duty, are situated within the controlled territory. The duties of these operators will ordinarily include the control of the adjacent main line signals, under orders received bytelephone or otherwise from the dispatcher. This local control of the signals possesses certain advantages and it is often desirable to retain such control even though a centralized traffic control system has been provided which permits these signals to be controlled from the dispatchers ofiice without the intervention of the local operators. This is particularly the case when the main line tracks are signaled for either direction of operation.

One object of the present invention is the provision of means whereby the signals governing trafilc movements toward or away from such points are controlled jointly by the local operator and by the operator at the distant control ofiice, so that a signal can not be cleared or a given direction of traffic set up by either operator without the knowledge and cooperation of the other.

In the embodiment of my invention herein illustrated, this object is accomplished by the provisionof apparatus for controlling the trafiic direction which is under the control of the local operator, and by the provision of means for se ,lectively clearing the signal for one direction or the other under the control of the distant operator.

' Referring to the accompanying drawing, the reference characters *I and la. designate the track rails of a stretch of railway track over which 45 lllEtffiC moves in both directions between the passing tracks at the ends of the stretch. The track rails 'l and ta are divided by insulated joints 2 to ior'm track sections eachof which is identified by the reference character T with a distinguishing prefix, and each track section is provided with the usual track circuit comprising a track battery 3 and a track relay TR. Sections 5T and lT include the track switches identified by the references 5 and 1, respectively, and trafiic movements through the switch sections are governed by the signals bearing the general references 6 and 8, with identifying prefixes.

Each signal is controlled by a signal relay H identified on the drawing by a prefix corresponding to the signal it controls. plained in detail, signal RAG or BB5, depending upon the position of switch 5, governs trafiic movements from left to right through the single track stretch, its control limits extending to the opposing signal LA8 or LBB, while the latter signals govern traffic movements from right to left in accordance with the position of switch 1, their control limits extending to signal RAG or BB6.

It is to be understood that switch I is located at the hereinbefore mentioned junction point or yard at which the local operator is stationed. The signals LA8, LBB, or the opposing signals R8 may be cleared by that operator by moving a signal lever G8 from its normal position as shown to position L or B, respectively. The control of the direction of train movements through the single track stretch is efiected by the local operator by the energization of one or the other of a pair of interlocked stick relays LFS and RFS by the operation of a traffic lever F to its position L or R in accordance with the direction to be established.

The centralized traflic control system may be of any suitable type, and to illustrate the present invention it has been assumed that this is of the time code type such as is disclosed in a copending application for Remote control system, Serial No. 600,786, filed March 23, 1932, by Lloyd V. Lewis. The detailed operation of the system is immaterial as far as the present invention is con- 1 cerned, and it is deemed suflicient to point out that it includes a transmitting and receiving apparatus unit at the control ofiice as indicated by a dotted line rectangle bearing the legend C. T. C. oifice in the drawing, and that this apparatus is connected by line wires to various field station units controlled by the ofiice apparatus and located at spaced points along the trackway. Two of these units are indicated by dotted line rectangles in the drawing, and are identified by the legends Station 58 and "Station 18, these units being located adjacent the left-hand and right-hand ends of the single track stretch. Each station unit is arranged to control one or more signal control relays such as the relays designated RGHS and L8HS, in accordance with different code signals transmitted from the ofiice. To illustrate the present invention, it is deemed sufficient to point out that these stick relays may be located wherever de- As hereinafter exsired and that they may be individually picked up and released by the operator at the distant control ofiice. These signal control relays therefore provide the means whereby the operator in the dispatchers ofiice may exercise his control over the local circuits and apparatus.

It is believed that the apparatus of my inven-- tion may be most readily understood from a description of its operation under various conditions of train movement, and starting with the apparatus in the condition shown in the drawing it will be assumed that signal RAB is to be cleared for a movement from left to right through the stretch of single track. The signal control relays RSHS and LBHS and the signal relays RABI-I, RBBH, LABI-I and LBBI-I are deenergized, so that all the signals are at stop, and assuming the stretch unoccupied, all of the track relays TR are energized, so that a line circuit is closed from one terminal 15 of a suitable source of current at station 58, back contacts 9, l0 and H, of relays RBEI-I, RA5H and RSI-IS, front contacts l2, 13, I4 and I5 of the track relays 5TR, 4TR, STR and ITR, line relay L8H and thence over the common return wire 4 to the other terminal C of the same source of current. Relay L8H is energized over the circuit just traced so that a local circuit is completed from terminal B over back contacts l6 and ll of relays LBBH and LABI-I, front contact l8 of relay L8H, back contact 19 of the traffic direction stick relay RFS, through the winding of the similar relay LFS, contact L of traffic lever F to terminal C. Relay LFS will therefore be energized and the corresponding indication lamp LE will be lighted over a circuit including contact 20, to indicate that the established traffic direction is from right to left. Assume now that in accordance with the dispatchers orders the local operator moves lever F to the right. Relay LFS will release and complete a circuit from terminal B over contacts IS, IT, I8 and 2 I, relay RFS, contact R of lever F to terminal C, so that relay RFS will pick up, closing contact 22 to light lamp RE to indicate that the established direction of trafiic is from left to right. Relay RFS also closes its stick circuit which may be traced from terminal B over its own front contact 23 and winding, and over contact R of lever F to terminal C. It will be apparent from a consideration of the circuits just traced that the established direction of trafiic can not be changed by the local operator if one of the signal relays is energized to clear a signal governing traflic movements into the single track stretch, or if any portion of this stretch is occupied so that a track relay is released.

The distant operator, acting under order from the dispatcher, may now clear signal RAG or RBB, depending upon the position of switch 5, by energizing the signal relay RSI IS of the centralized trafiic control system. When relay RBI-IS is energized by the distant operator, contact II will open to release relay L8H, and if relay RFS has been energized by the local operator, a circuit will be closed from one terminal B of a source of current at station TS, front contact 38 of relay RFS, back contacts 24, 25 and 26 of relays LBSH, LA8H and L8I-IS, front contacts 21, 28, 29 and 3B of the track relays 'ITR, GTR, 4TB and 5TR, front contact 3! of relay RBI-IS, switch circuit controller contact 32 controlled by switch 5, and thence through the winding of the signal relay RAGI-I or RBGH and over line wire 4 to terminal 0 of the same source, so that the signal relay will become energized to clear the corresponding signal RAB or RBB.

The local operator may now move his signal lever G8 to the right to clear signal R8 for the same direction, as indicated by a dotted line connection in the drawing. Signal RAG or RB6 may be put to stop by the distant operator by releasing relay RSHS or by the local operator by moving lever F to the left, but neither operator can alone effect the clearing of a signal for the opposite direction.

In order to clear signal LA8 or LB8, the local operator will move lever F to the left, and the distant operator will release relay RBHS, and if the stretch is unoccupied and all signals are at stop, relays L8H and LFS will become energized as hereinbefore explained and the latter relay will complete its stick circuit including contact 33, similar to that for relay RFS already described. The local operator will also move signal lever G8 to the left, while the distant operator will effect the energization of relay LBI-IS, com:- pleting a circuit from terminal B, contact L of signal lever G8, front contacts 34, 35 and 36 of relays LFS, L8H and L8I-IS, circuit controller contact 3'! controlled by switch I, thence through the winding of relay LABH or LBBH to terminal C to clear signal LAB or LBB, depending upon the position of switch 1. It will be seen that the line relay L8H serves both as a signal relay for controlling the signals for one direction and as a trafiic relay for governing the reversal of traffic direction by the local operator.

The distant operator may now clear signal L6 for the same direction by the operation of a stick relay, not shown, which is similar to relay L8HS but which is located at station 58, or this signal may be controlled automatically, the control circuits for signal L6 not being shown as they form no part of the present invention. In this case also it will be evident that signal LAB or LE8 can be put to stop either by the distant operator or by the local operator, but that neither operator alone is able to restore the original direction of traffic and clear a signal leading into the single stretch of traffic from the opposite direction.

It will be apparent from the foregoing that in part the trafiic direction is controlled by the distant operator because in order to reverse trafilc he must deenergize one of the signal control relays RBHS and L8HS and energize the other, by means of the centralized trafllc control system, but that this is without efiect unless the local operator cooperates by operating his traflic lever F to a corresponding position when conditions are proper. It will also be apparent that either operator may restore a cleared signal manually to stop at any time.

Although I have for simplicity shown each of the signals as being of the two-position type, it is to be understood that in practice these will usually be controlled automatically to a third position in accordance with the condition of the next signal in advance for the same direction, and further, that intermediate signals may also be employed and that these signals as well as the head block signals may be provided with directional control in accordance with the well known principles of absolute permissive block signaling.

In view of the foregoing description of the operation of the apparatus of my invention, it will be clear that the opposing signals leading into the single track stretch are controlled by operators acting under orders from the dispatcher over two independent channels and if the dispatoliers orders as transmitted over either of these channels are improperly executed no dangerous situation will arise. One of these channels includes telephonic or other communication with the local operator who presumably is best informed as to local conditions affecting the admission of trains to the single track stretch, while the other channel is under the direct supervision of another operator, usually one stationed in the dispatchers ofiice, who is better informed than the local operator as to train movements in general, and in particular as to the locations and movements of trains at other points, and the safety of operation of trains is thereby enhanced.

Although I have herein shown and described only one form of apparatus embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In a centralized traffic controlling system for railroads, a single track stretch, two signals including one at each end of the stretch for governing the movement of trainc in opposite directions into the stretch, a remotely controlled relay at each end of the stretch, a pair of directional relays including one for each direction, a manually controlled pickup circuit for each directional relay closed only when said stretch is unoccupied, a stick circuit for each directional relay including its own front contact and a back contact of the other directional relay, and control circuits for said signals controlled in accordance with traffic conditions in said stretch, each including a front contact of the remote controlled relay at the same end of the stretch and a front contact of the directional relay for the corresponding direction.

2. In combination with a stretch of railway track, two signals including one at each end of the stretch for governing the movement of traflie in opposite directions into said stretch, a line circuit for each direction each including a line relay for controlling the signal for the corresponding direction in accordance with traflic conditions in said stretch, manually controllable traffic direction controlling means at one end of the stretch operable to reverse the traffic direction only when the adjacent line relay is energized and the signal it controls is at stop, and means manually controlled from a distant point for controlling said line circuits to clear one signal or the other in accordance with the condition of said trafiic direction controlling means.

3. In combination with astretch of railway track, two signals including one at each end of the stretch for governing the movement of traflic in opposite directions into said stretch, a line circuit for each direction each including a line relay for controlling the signal for the corresponding direction in accordance with traffic conditions in said stretch, two manually controllable relays at one end of the stretch independently controllable from different points, means effective only when both said manually operable relays are energized and the adjacent line relay is also energized for clearing the signal at the same end of the stretch, and means effective only when both said manually operable relays are deenergized for energizing the line relay at the opposite end of the stretch to clear the opposing signal.

4. In a centralized traffic controlling system for railroads, a stretch of railway track divided into track sections each provided with a track relay, a signal at each end of the stretch for governing the movement of trafiic into the stretch, a line circuit for each signal each including contacts of each track rela directional selecting means manually operable only when the line circuit for at least one of said signals is closed, signal control means operable from a remotely located control ofiice for selectively clearing one signal or the other in accordance with the condition of said direction selecting means and of the line circuit for such signal, and means controlled by said direction selecting means for preventing a change in the condition of said direction selecting means when any portion of the stretch is occupied.

RONALD A. McCANN. 

